This project is concerned with solubilization, characterization and purification of gonadotropin and prolactin receptors and adenylate cyclase and testis and ovary. In addition to analyzing the properties of gonadotropin receptors and adenylate cyclase, and of the physical and functional relationships of the binding site and the enzyme complex in the cell membrane and in solution. Recent findings suggest that phosphorylation of the guanyl nucleotide regulatory protein mediates activation of adenylate cyclase during hormone action, and that this process can be modulated by changes in calcium availability.